In an era of record-setting election spending, don’t expect massive corporations such as Berkshire Hathaway, Charles Schwab and Cardinal Health to volunteer one iota more information about their political activity than they must.

That’s because they’re among the nation’s lousiest large, publicly held companies when it comes to freely disclosing and managing political spending, according to a study released Tuesday by the nonpartisan Center for Political Accountability and University of Pennsylvania Wharton School’s Carol and Lawrence Zicklin Center for Business Ethics Research.

Familiar S&P 200 companies such as Wells Fargo, Proctor & Gamble, General Electric, United Parcel Service and Pfizer also ranked highly.

The study looks at whether companies publish names of top political money decision makers, adhere to policies governing corporate political expenditures and publicly disclose payments to nonprofits and trade associations that may use the money for political purposes.

Costco, the Walt Disney Company and Capital One Financial made the greatest strides from 2011. Attribute that, in large part, to companies’ acute sense of public perception, self-preservation and shareholder desire to know how companies are playing politics, says Bruce Freed, president of the Center for Political Accountability.

“They’re recognizing that it’s something they should be doing: It’s good corporate governance and it’s good protection,” Freed said. “Political spending it risky, and they’re under understanding that they need policies and practices in place to manage that risk.”

For Microsoft, which placed second overall, it makes business sense to be ever more open about corporate political activity, says Dan Bross, the software giant’s senior director for corporate citizenship.

“Trust in many large institutions, including corporations, is at an all-time low,” he said. “So corporations need to think more about issues of transparency, governance, responsibility, openness and disclosure.”